T Nation

Vit A Supplements (Retinol) KILL Vit D / Raise Colon Cancer risk

It also has an effect on:

Muscle strength
immune systems
secretion and regulation of insulin by your pancreas
heart and blood pressure regulation
Brain activity

Pretty important stuff.

A few weeks ago, the British Medical Journal published a remarkable paper – remarkable that it studied more than 500,000 subjects, remarkable that it had 56 (fifty-six) authors, remarkable that it confirmed low vitamin D levels obtained in the past are a risk factor for developing colon cancer in the future…

However, the most remarkable part of the paper is that the 56 scientists minimized the true significance of their own research. They found that vitamin A, EVEN IN RELATIVELY LOW AMOUNTS, appears to thwart vitamin D’s association with reduced rates of colon cancer. …also the paper notes that alcohol thwarts the effects of vitamin D as well.

Hidden on page eight of the paper is one sentence and a small table, which shows that the benefits of vitamin D are almost entirely negated in those with the highest vitamin A intake. And the retinol intake did not have to be that high in these older adults to begin to negate vitamin D’s effects, about 3,000 IU/day, which is contained in many multi vitamins and in cod liver oil.

http://www.bmj.com/cgi/content/full/340/jan21_3/b5500

Naturally, vitamin A production is tightly controlled in your body. The substrate of the vitamin A, are carotenoids from vegetables in your intestine. Your body converts these carotenoid substrates to exactly the right amount of retinol. However, when you take vitamin A as retinol directly, such as in cod liver oil, you bypass all the natural controls in this closed system.

Ideally, youâ??ll want to provide all the vitamin A and vitamin D substrate your body needs in such a way that your body can regulate both systems naturally.

This is best done by eating colorful vegetables (for vitamin A) and by exposing your skin to sun every day (for vitamin D).

Interaction with Calcium: Also the study showed that higher intake of dietary calcium showed some evidence of association with a reduced cancer risk association, particularly in the rectal anatomical sub-site.

Sources:


www.bmj.com
www.mercola.com

What you can do?

  1. Obviously don’t take a multi with retinol, rather obtain Vit A substrates from whole foods, or a multi that has natural caretenoids in it.
  2. Also avoid or limit alcohol intake
  3. Ensure adequate calcium is obtained
  4. Ensure adequate Vit D from sun, supplement, and or food combo.
  5. Test Vit D levels

BT

You’ve had some really good finds lately.

Thanks Chimera. bump

Yes, there is no reason to take Vitamin A as Vitamin A itself – retinol – and there are reasons not to do it. While the epidemilogical study in question (I didn’t save the reference) does not prove causation, supplemental retinol intake is correlated with lower life expectancy, and is the only vitamin for which this is the case.

Everything in balance. I wish more doctors could figure this out…

[quote]Bill Roberts wrote:
Yes, there is no reason to take Vitamin A as Vitamin A itself – retinol – and there are reasons not to do it. While the epidemilogical study in question (I didn’t save the reference) does not prove causation, supplemental retinol intake is correlated with lower life expectancy, and is the only vitamin for which this is the case.[/quote]

For what it’s worth, I only used such a drastic sounding (and not experimentally proven) title for dramatic flare.

I haven’t taken retinol for a while, but not because I knew of any reason not to. Not to sounds braggy, but it was either simply because I either didn’t take a multi at the time, or I took/take a decent quality multi that uses natural caretenoids, natural vit E, mineral chelates, etc. The only main thing it lacks is potassium, (which thank you bill) I also take supplementally now, and I adjust my dose of all the above according to my predicted/calculated food intake. AS I’m currently dieting I take 2 grams potassium, in addition to a 2/3 dose multi (4 pills split into two doses). I also several other supplements that are non vits/mins, but anyways…

…The point is that moderation is just as important as realizing what your body does (more vit D, fish oil, etc) and doesn’t need (retinol), and what it can do better with and without. Also remember that RDA values are only benchmarks and you need to determine for yourself what your changing needs are.

Interesting. I’m gonna check my multi for vitamin A… good thing I dont drink milk anymore too!

I thought about potassium supplementation myself… I get tons of sodium and eat a decent amount of fruits and veggies but as an athlete idk if I get enough potassium

Bump for those that may have missed this info.

I totally agree that all of your vitamin reqs should come from food (ie. veggies etc). But in reality that rarely happens. I don’t use Vit A in any form on it’s own but it is in multi-vitamins for a reason. The different forms play pretty big roles in just day to day cell function.

I know this article http://la.rsmjournals.com/cgi/reprint/5/2/239 isn’t recent but based on what I’ve learned, it still pretty relevant. Vit A def was found to lead to infertility and degeneration of the retina.

I wouldn’t stop taking a multi just because it has Vit A.

Well, one can lead a horse to water but can’t make him drink; to each his own, etc.

However, it’s possible that what is happening is that the facts are not being communicated properly.

Vitamin A can be supplied as retinol or as beta-carotene.

Beta carotene has no toxicity issues. The only problem associated with taking it is if one takes a vast amount, and then the problem is simply the skin turning orange. (This has happened to me twice: back in the day when Met-Rx was the best MRP and I was consuming six per day; and last year when I was routinely adding pumpkin to my protein shakes.)

Retinol has toxicity associated with it at any supplemental dose that has been studied.

That alone should be enough reason to choose a product that supplies Vitamin A as beta carotene rather than as retinol.

Another reason could be: If the company is so ignorant as to still be supplying it as retinol, when the above information has been well known in science and in the supplement industry for quite some time, how ignorant or low-quality may the rest of their formulation be?

(The answer is, Typically pretty ignorant or low quality: for example such a formulation will probably use d,l-alpha-tocopherol as their Vitamin E source.)

[quote]Bill Roberts wrote:
Well, one can lead a horse to water but can’t make him drink; to each his own, etc.

However, it’s possible that what is happening is that the facts are not being communicated properly.

[/quote]

Thanks for clarifying Bill…I initially skimmed the first post and definitely read it wrong.

It is (or was when it came out) a surprising fact.

It was known that retinol was toxic when megadosed, but the discovery that quite modest supplementation is correlated with worse outcomes was certainly unexpected by most or perhaps by everyone.

So I can see where it would be quite natural to assume that there couldn’t be an actual problem.